Digital-to-time converters (DTC) are promising building blocks for future phase modulators, as well as for use in pulse width modulation, and the like. A DTC is a building block which delays incoming signal edges according to digital tuning information at its input. For example, a DTC may convert a digital signal or a digital value to a time delay. It may provide particular delays that can be used for triggering, syncing, delaying, and/or gating certain events. In a phase modulator, for instance, the DTC may act as a variable delay element which alters the phase of an incoming quasi periodic signal by dynamically changing its delay.
There are some multi-stage approaches that are currently used to construct high dynamic range DTCs. For example, in a first stage, coarse delays may be generated by selecting coarse phases of the input signal. In a second stage, an independent delay element may be used to interpolate in between the coarse phases. Problems may emerge, however, if the tuning range of the independent delay element does not fit perfectly into the coarse intervals. This may happen, for instance, when the gain of the independent delay is not perfectly known and/or due to variations of the coarse delay elements.